Apparatus for and process of purifying gas



A. L. STEVENS.

TILED SEPT.

Patented J u1); 25, 1922.

2 SHEVSVSHEET I @y /Q f APPARATUS FR AND PROCESS 0F PURFFYJNG GAS.

APPLiCATUN A. L. STEVENS.

APPARATUS FOR AND PROCESS 0F PURIFYENG GAS.

APPLICATION FILED SEPTJZ. 1919.

1 ,423,696, y Patented July 25, 1922.

2 SHEETSSHEET 2. m f ix I, Qr

UNITED STATES ARTHUR I.. STEVENS, 0F CHICAGO, ILLINOIS.

APPARATUS FOR. AND PROCESS 0F PURIFYING GAS.

Specication of Letters Patent.

Patented July 25, 1922.

Application filed September 22, 1919. Serial No. 325,442.

To all whom t may concern.'

Be it known that I, ARTHUR L. STEVENS, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in A paratus for andProcesses of Purifying as, of which the following is a specification. p

y invention relates to an apparatus for and method of purifying gas,particularly coal gas.

In the manufacture of coal gas the gas from the retort is passed throughscrubbers which remove a large portion of the impurities from the gas,which scrubbers, however, fail to remove minute particles of foreignmatter, for example, tar, which may exist in the gas in the form of avapor or fog and pass along with it from the scrubber. The scrubberscommonly employed are also incapable of eliminating from the gas suchsubstances for example as sulphur and carbon dioxide.

It has been found that when gas containing tar in a fog or vapor ispassed through a body of hot liquid tar, the tar in the gas will have anaiiinity for or tendency to adhere to the body of tar through which thegas is passed. lt has also been found that sulphur and carbon dioxidemay be eliminated from gasb passing the gas through a body of absor ingli uid, for example, lime water. In order to eiliminate effectively anyof these undesirable substances, it is essential that the gas be broughtinto very intimate contact with the body of liquid through which it ispassed. One of the objects of my invention is to provide an improvedapparatus whereby the gas will be very finely subdivided and broughtinto intimate contact with the liquid through which it is passed, tar,lime water, or other cleansing fluid; and to this end I provide anaggregation of relatively small bodies, preferably spherical and ofsmooth surface, which are submerged in the li uid and are supported bysuitable means, or example, grates or perforated plates through whichthe gas is compelled to pass. Thus the gas in passing through the gratesor perforated plates is divided into small streams and in passingthrough the tortuous paths constituted by the spherical bodies or balls,1s further subdivided still more minutely. By this means every particleof the as is brought into intimate Contact with the iquid,

and the elimination of the undesirable constltuents in the gas iscompletely ellected.

Afurther ob]ect of in invention is to prov1de improved means fbr thecirculation of the body of liquid through which the gas is passed, whichcomprises a by-pass pipe 1n association with the reservoir containingthe liquid, the pressure maintained in the by-pass pipe being sufficientto compel the gasto pass through the portion of the body of liquid inwhich the balls are arran ed.

The invention consists in the nove andy improved constructions,arrangements and devices to be hereinafter described and claimed forcarrying out the above stated objects and such other objects as willhereinafter appear.

The invention is illustrated in certain preferred embodiments in theaccompanying drawings, wherein:

Fig. 1 is a vertical sectional view of an apparatus embodying theprinciples of my invention;

Fig. 2 is paratus;

Fig. 3 is a horizontal section on the line 3-3 of Fig. 2; and

Fig. 4 is a vertical sectional view illustrating a modified form ofapparatus.

Like characters of reference designate like parts in the several figuresof the drawing.

In Figs. l to 3 inclusive of the drawing, I' have shown a novel form ofapparatus in which the operation of removing tar may be practiced and inwhich 1 is a cylindrical casing built up of sections, 2, 3, 4, 5 and 6.

he casing may be formed of cast iron or any other suitable material.Between the sections 3 and 4 and 4 and 5 I interpose grates orperforated plates 7, shown in detail in Fig. 3, which are preferablyformed with a series of narrow slots 8. The grates or perforated plates7 are held in place by any suitable means, preferably by clamping thembetween theadjacent flanges of the sections 3 and 4 and 4 and 5,respectively.

Gas is forced from the ordinary scrubber, in which a considerableportion of the impurities have been removed, and the gas cooledincidentally in the scrubbing operation, into the apparatus as hereshown through the main 9 which passes into the top 10 of the apparatusand through the openings 11 formed in the grates 7. The lower end of thegas main or conduit 9 is formed with a plurality of orifices, prefa sideelevational view of the aperably narrow vertical slots 12, and thebottom of the pipe is closed by means of the rap 13, By this arrangementthe gas is forced out through the slots 12 in radial jets, and thenupwardly through the gratos 7. A number of relatively small bodies orobjects 14, preferably spherical und smooth of surface, and uniform insize, are placed between the grates 7, T in the reservoir around the gasconduit, hand holes 15 being formed in the easing for the insertion ofthe same. The bodies 14 ma f be of any suitP able material. I haveJfount that glass balls approximately one inch in diameter areparticularly desirable for the purpose, although other objects such asshot or gravel might also be used, but perhaps to less advantage. Aheating eoil 16 maybe provided for main taining the tar in a fluidstate.

The reservoir is filled to the level X, X, with a liquid which, for theremoval ot tar fog from gas will preferably be a b ody of tar. A by-passor return pipe 1T is provided in association with the reservoir toprovide 'for the circulation ot' the tar in the vessel set up by therising of the gus vthrough the body of tar and also in some degree bythe rising of the heated tar in the heater 16. The introduction of thegas into the vessel at the point above that at whirh the lower end ofthe return pipe 1 7 enters the vessel prevents the passing of any gas upwardly 'through the return pipe.

At the top ot the apparatus is provided a discharge nia-in 18. ln orderto prevent carrying over large globules of tar into the discharge main,due to the rush ot' gus through the body of tar, 1 provide a horizontalbaille member 19 which is suspended around the inflow pipe by means ofthreaded studs 20, the upper ends of which are srrewed into the flangesformed on the seetions 2 and 3. Any tar Whieh splashes against thebottom of the baille member drops bark into the apparatus, the gas beingforced arouml the edges of the baille member.

I provide means for maintaining the level of tar constant on the line X,X, regardless of any variations in the gas pressure. The exoess tarremoved from the gas may pass out 'of the apparatus at the bottomthrough the pipe 21 and through the legs 2Q, 2i and 24, and finally to amain'Q leading to a suitable reservoir. 1n order thatV no siphonieaction should oeeur, I place at the bend 26 in the pipe a small pipe 27leading into the upper art of the easin to break the vacuum at t isoint. The pipe Q7 also serves to equalize tlie pressure in the bend 26with the pressuie inside the easing. In order that the differencebetween the internal gas pressure and atmospheric pressure may not lowerthe level belowT the line X, X

by forcing liquid tar out of the apparatus,

I provide the additional stand pipe 28 `for halanring this pressure,this pipe being open at the top to the atmosphere. The differential inhydrostatic; pressure in pipes J3 and Q4 equal to the pressure at Whirhthe gas is delivered through the main 11%. As u result of this theliquid in the reservoir is maintained at a constant level, even whenvarying pressures are employed in the gas main. I provide the apparatuswith a drain 29 for removing the liquid tar from the rasing controlledby u valve 3l), and which is connected to the piperQ. Additional handholes 3l are provided at convenient points in the sides of the apparatusfor cleaning purposes. The apparatus rests ou the base 232. pipe 33 maybe provided l'or blowing out. the apparatus in Cleaning.

rhe gas is forced into the apparatus through the main il und on passingthrough the slots 1:2 it is forced outuuiriillyV in radial jets and isuniformly distributed underneath the lower grate 7. lt is then Forred upivardly through this grate against the hydro static head ol liquid tar.lu passing through the grate T it is divided into small streams undforced to take the tortuous paths hrtivren the bulls il, thereby beingl'urther subdivided into streams, and the minute partirles of tarsuspended in the are brought inte-fiery intimate relationship with Yearh other and with the body ot' liquid lar iu the reservoir.

ln Fig. 4 l have illustrated u inodiiied torni of apparatus which may beused for recovering beuzol, u'hieh is valuable as a liv-produrt, or foreliminating sulphur from the gus. The apparatus is substantially thesuine as has been heretofore described. lf

it is desired to eliminate sulphur from the gas, limewater may beemployed in the saine way as the liquid tar is employed in removing thetar fog from the gas. The limewae ter may be introduced into theapparatus through the pipe 34. lt will also be evi deut that this vformof apparatus may be used for rerovering benzol Vfrom the gas. For thispurpose tar distillate, whirh has un affinity for benaol, may heintrodured into the apparatus by means of the pipe B4.

1 have 'found that the ellieieney of the apparatus does not depend uponthe velot'ity of the gas through the liquid, as equally good results.muy be obtained when the pres sure of the gas is relatively lovv, aswhen it is relatively high, because of the minute streams the gas issubdivided into and the tortuous pathsi they are Aforced to travel inpassing through the aggregate of small bodies.

lt will be observed that l have provided an apparatus, simple inconstruction, without moving parts, adapted `for Continuous operation,with all outlets other than the discharge main, sealed at all timesagainst the escape of gas, and with provision for continuous circulationof the liquid contents Within a closed path through the casing andby-pass, with automatically maintained liquid level by automaticdischarge of any increase of the volume of liquid by virtue ofimpurities separated from the gas.

lllhen liquid tar is used as described, the circulation provided servesnot only to fa eilitate the passage ot' the gas through the tar andthrough the minute and numerous passages between the glass balls or thelike, but, With the heating coil in service, such circulation serves tokeep the entire body of tar sufficiently fluid and to permit and assistthe as to flow throughout the entire mass of gass balls or the likeinstead of establishing relatively limited and definite lines of flowthrou li only a portion of the mass of balls. T is also neutralizes anytendency of the tar to gum or close certain of the passages between suchbodies as the glass balls, and overcomes the tendency of the gas toforce out or carry away the tar 'from the interstices between the smallballs as might happen Without means providing for a constant circulationand supply et tar.

When other li nids are used, such as lime Water or other liuids whichdiffer from the impurities in the gas for which they have an aliinity,such circulation tends to produce a more homogeneous condition wherebythe whole body of liquid continues to act elliciently until the oint ofsaturation or near saturation is reac ed.

It will be apparent to those skilled in the art that the apparatus iscapable of 'various modifications 1n the matter of details ofconstruction and arrangement of parts, and I do not limit the inventionto the details of construction and arrangements described except only inso far as certain of the appended claims are so limited.

The word ainity as employed in certain of the claims is used in a broadsense to intend, for example, either a cohesive or reactive ailinity asbetween the impurities in the gas and the body of liquid Vthrough whichthe gas is passe l claim:

l. A gas purifying apparatus comprising in combinatlon a reservoir forcontaining a purifying liquid, a luy-pass pipe connected with saidreservoir at an upper and lower level, a gas supply conduit discharginginto said reservoir at an intermediate level, a grate in said reservoirabove the discharge end of said su ply pipe, a body of small objects ofa con guration to provide voids be tween them supported by said Ierratefor subdividingr the gas into minute streams, and a gas dischargeconduit connected with said reservoir for conducting away 'the cleaned g2. A gas purifying apparatus comprising in combination a reservoir forcontaining a pnrifying liquid, a by-'pass pipe connected with saidreservoir at an upper and lower level, a gas supply conduit discharginginto said reservoir at an intermediate level, a pair of grates in saidreservoir above the discharge end of said supply pipe, a body of smooth,small objects supported between said grates for suhdividing the gas intominute streams, and a gas discharge conduit connected with saidreservoir for conductingaway the cleaned gas.

3. A gas purifying apparatus comprising in combination a reservoir forcontaining a purifying liquid, a by-pass pipe connected with saidreservoir at an upper and lower level, a as supply conduit leadin to anintermediate level and provided witht a plurality of vertical slots fordischarging the ras 1n lateral streams into said reservoir, a

ody oit smooth spherical objects in said liquid through which the gas isadapted to pass for dividing said gas into a plurality of small streams,and a gas discharge conduit connected with said reservoir for conductingaway the cleaned gas.

4. A gas purifying apparatus comprising in combination a reservoir forcontainingr a purifying liquid, a by-pass pipe connected with saidreservoir at an upper and lower level, a gas supply conduit leading' toan intermediate ievel, said conduit being closed at the end and providedwith a ilui'ality of vertical slots adjacent said end whereby thc gas isdischargeiil laterally into the liquid 1n said reservoir, a body ofsmooth, small objects supported in said liquid above the discharge endof said supply pipe for dividing the gas into minute streams andbringringr the same into intimate contact with the l1 uid, and a ,gasdischarge conduit connectedl with the upper portion of said reservoirfor conducting' away the cleaned gas.

A gas purifying apparatus comprising in combination a reservoir forcontaining,r a purifying liquid, a gas supply conduit for discharginggas into said liquid, a body of small objects in. said reservoir forsubdividing the gas into minute streams, and means for maintaining aconstant liquid level in said reservoir and for conducting away excessliquid comprisingT a' pipe connected with the lower portlon ot saidreservoir and eX- tending upwardly to a point coincidinp with the liquidlevel in said reservoir and connected to said reservoir above saidliquid level, said pipe ruiming straight downwardly and upwardly to forma U-shaped section and terminating),r at a point above the liquid level,and provided With an outlet in the terminal portion of said U-section ata point below the liquid level. s

G. A gas purifying, apparatus comprisiincr in combination a reservoircontaining liquid tar, means for maintaining said tar at a constantlevel, a ley-pass pipe connected with y gas.

` gas.

said reservoir at the upper level of said tar and with the lower portionof said reservoir, a gas supply conduit dischargin into said tar, a bodyof objects of a con guration to provide voids between them which are insaid tar for dividing said gas into minute streams and bringing the sameinto intimate contact with said tar, and a gas discharge conduitconnected with said reservoir for conducting away the cleaned gas. 7. Agas purifying apparatus comprisin incombination a reservoir containingliquid tar, means for maintaining said tar at a constant level, aby-pass pipe connected with said reservoir at the upper level of saidtar and with the lower portion of said reservoir, a gas supply conduitdischarging into said tar, a bodyof objects of a configuration toprovide voids between them which are in said tar for dividing said gasinto minute streams and bringing the same into intimate contact withsaid tar, and a heater in the lower portion of said reservoir formaintaining the tar at the proper fluidity, and a gas discharge conduitconnected with said reservoir for conducting away the cleaned 8. A gaspurifying apparatus comprisin in combination a reservoir containingliquid tar, means for maintaining a constant level of tar, and forconducting away excess tar, a by-pass pipe connected with the reservoirat the upper level of said tar, and with the lower portion of saidreservoir, a gas supply pipe extending from the upper portion of saidreservoir centrally thereof, and terminating at a point above the lowerconnection of said by-pass pipe, a grate across said reservoir above thedischarge end of said sup ly pipe, a body of small objects of a conguration to provide voids between them which are in the tar supported bysaid grate for dividing the gas into minute streams and bringin the sameinto intimate contact with sald tar, a heater in the lower portion ofsaid reservoir for maintaining the tar at the proper fluidity, and a gasdischarge conduit connected with the` upper portion of said reservoirfor conducting away the cleaned gas.

9. Apparatus for removing the residual tar fog from gas comprising achamber for containing a liquid having an aiiinit for the particles oftar in the gas, a condmt for introducing the gasinto said chamber so asto pass through the liquid, a body of small objects in said liquidadapted to break up the gas passing through the liquid into a pluralityof small streams and to repeatedly change the direction of such streams,and a dischar conduit oonneclted writh said, chamber or conducting awaythe cleaned 10. Apparatus for removing the residual tar from gascomprising a chamber for conin the vessel and submerged in the liquid,

taining liquid tar, a conduit for introducing the gas into said chamberso as to pass through said tar, a body of small, smooth, sphericalobjects in said tar adapted to break up the gas passing through the tarinto a plurality of small streams and to repeatedly change the directionof such streams, and a discharge conduit connected with said chamber forconducting away the cleaned gas.

11.V A gas cleaning apparatus comprising in combination, a vesselcontaining a bodv of liquid having an ainity for the impuritiessuspended in the gas, a mass of small solids of a configuration toprovide v'oids between them which are supported midway in the vessel andsubmerged in the liquid, means for introducing the gas into the body ofliquid below said mass of small solids, and a return by-pass forconducting the liquid from a point above the mass of small so ids to theportion of the liquid below said mass and below the point of entrance ofthe gas.

12. A gas cleaning apparatus comprising, in combination, a vesselcontaining a body of liquid having an ailinity for the impuritiessuspended in the gas, a mass of small solids of a configuration toprovide voids between them which are supported midway means forintroducing the gas into the body of liquid below said mass of smallsolids, a return by-pass for conducting the li uid from a point abovethe mass of small so ids to the ortion of the liquid below said mass andbe ow the pointoiI entrance of the gas, and means for automaticallydischarging the excess liquid as augmented by the im'- purities of thegas so as to maintain said body of liquid at a constant level.

13. A gas cleaning apparatus com rising, in combination, a vesselcontaining a body of liquid having an ailinity for the impuritiessuspended in the gas, a grid extending across the vessel above the pointand within the body of liquid, a mass of small solids of a configurationto provide voids between them which are supported on said grid andwithin the liquid, a gas pipe extending through said mass of smallsolids and through the H5 grid for introducing the gas into the bod)T ofliquid below said grid, and a return bypass for conducting liquid freina; point above the mass of small solids to the portion of the liquidbelow said mass and below the point of entrance of the gas.

14. Method of removing minute tar par ticles from gas which consists inproducing a continuous circulation of tar through the interstices of andthen around a mass of small solids of a configuration providing voidsbetween them, and introducing the gas into said stream of liquid at apoint in advance of and adjacent to said mass.

15. Method of removing minute tar particles from gas which consistsinproducing a continuous circulation-of tar first upwardly through theinterstices of and then downwardly around a mass of small solids of aconfiguration providing voids between them, and introducing gas into therising Stream of tar at a, point above the lowest point of the streamand below said mass of solids.

16. Method of removing minute tar particles from gas which consists inproducing a continuous circulationof tar first upwardly through theinterstices of and then downwardly around a mass of small solids of aconfiguration providing voids between them, introducing gas into therising stream of tar at a point above the lowest point of the stream andbelow said mass of solids, and discharging the tar from said body as thebody is augmented by accretions of tar par- 20 ticles from the gas.

ARTHUR L. STEVENS.

, Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,423,696, grantedJuly 25, 1922, upon the application of Arthur L. Stevens, of Chicago,Illinois, for an improvement in Apparatus for and Processes of PurifyingGas. an error appears in the printed specification requiring correctionas follows: Page 3, line 72, claim 2, strike out tlie word smooth, andafter the word objects insert the words of a configuration to provide'voids between them; und that the said Letters Patent should be readwith this correction therein that the same may conform to the record ofthe case in the Patent Oice.

Signed and sealed this 9th day of January, A. D., 1923.

[um] KARL FENNING,

Acting ommisaioner of Patents.

